A method of separating an organic solvent which may easily separate and recover an organic solvent from a mixed solution containing the organic solvent, and an organic solvent separation system capable of performing the same are disclosed herein. In some embodiments, the method includes introducing a first mixed solution into a first distillation column to recover an organic solvent and discharge a first fraction containing an unrecovered organic solvent and a high boiling point compound A to a bottom of the column, introducing a second mixed solution into a second distillation column to recover organic solvent and discharge a second fraction containing an unrecovered organic solvent and a high boiling point compound B, and introducing the first fraction and the second fraction into a third distillation column to recover an organic solvent-rich fraction and a high boiling point compound-rich fraction.